THE HIGHER HYDRIDOSPHEROSILOXANES - SYNTHESIS AND STRUCTURES OF HNSINO1.5N (N=12, 14, 16, 18)

摘要

The preparation of the four pure compounds O-h-H8Si8O12, D-5h-H10Si10O15, D-2d-H12Si12O18 and D-3h-H14Si14O21 is described in detail. These compounds were prepared in 0.5, 3.6, 3.5 and 1.1% yields, respectively, based on the starting material HSiCl3. The synthesis was also scaled up to make gram quantities of these compounds. In addition, preparative gas chromatography was used to isolate mixtures of isomers of H14Si14O21 and H16Si16O24, from which the H-1 and Si-29 NMR chemical shift values of particular isomers, and in one case the X-ray crystal structure, were determined. The structure of the major isomer of H16Si16O24 is proposed, based on a complete enumeration of all possible isomers of this composition that have chemically reasonable structures and the strong correlation observed between topological features of the polyhedral structures of these compounds and Si-29{H-1} NMR chemical shift values. This isomer has idealized D-4d symmetry, with two 4-rings and eight 5-rings arranged such that there are two sets of eight symmetry-equivalent silicon atoms. [References: 45]